From: Eli Zaretskii <eliz@gnu.org>
Date: Sat, 30 Apr 2022 09:00:33 +0000 (+0300)
Subject: ; Minor fixes of documentation of double-buffering on MS-Windows
X-Git-Tag: emacs-29.0.90~1931^2~198
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=03561b4aad87bbc32131e026e253628e8cef9f2f;p=emacs.git

; Minor fixes of documentation of double-buffering on MS-Windows

* etc/NEWS: Improve and expand wording of the entry about
double-buffering on MS-Windows.

* src/w32fns.c (w32_set_inhibit_double_buffering): Fix commentary.
---

diff --git a/etc/NEWS b/etc/NEWS
index 5c2f152a127..30882ed2fe7 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2147,11 +2147,19 @@ to preserve the old behavior, apply
 ** MS-Windows
 
 ---
-*** Emacs now supports double buffering on MS Windows to reduce flicker.
-This leads to a noticable reduction in the amount of graphics flicker
-during redisplay on many systems, but can also make painting slower.
-If that happens, it can be disabled by setting the
-'inhibit-double-buffering' frame parameter.
+*** Emacs now supports double-buffering on MS-Windows to reduce display flicker.
+(This was supported on Free systems since Emacs 26.1.)
+
+To disable double-buffering (e.g., if it causes display problems), set
+the frame parameter 'inhibit-double-buffering' to a non-nil value.
+You can do that either by adding
+
+   '(inhibit-double-buffering . t)
+
+to 'default-frame-alist', or by modifying the frame parameters of the
+selected frame by evaluating
+
+   (modify-frame-parameters nil '((inhibit-double-buffering . t)))
 
 +++
 *** Emacs now supports system dark mode.
diff --git a/src/w32fns.c b/src/w32fns.c
index fb71fecd95a..ead1549d557 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -1802,7 +1802,7 @@ w32_set_tool_bar_lines (struct frame *f, Lisp_Object value, Lisp_Object oldval)
   w32_change_tool_bar_height (f, nlines * FRAME_LINE_HEIGHT (f));
 }
 
-/* Enable or disable double buffering on F.
+/* Enable or disable double buffering on frame F.
 
    When double buffering is enabled, all drawing happens on a back
    buffer (a bitmap), which is then displayed as a single operation